Ordering of alkane isomers by means of connectivity indices

• Main Authors: Gutman Ivan, Vidović Dušica, Nedić Anka
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2002-01-01
• Series: Journal of the Serbian Chemical Society
• Subjects: connectivity index; randić index; alkanes; isomer ordering.
• Online Access: http://www.doiserbia.nb.rs/img/doi/0352-5139/2002/0352-51390202087G.pdf

The connectivity index of an organic molecule whose molecular graph is Gis defined as C(λ)=Σ(δuδv)λwhere δu is the degree of the vertex u in G, where the summation goes over all pairs of adjacent vertices of G and where λ is a pertinently chosen exponent. The usual value of λ is –1/2, in which case χ=C(–1/2) is referred to as the Randić index. The ordering of isomeric alkanes according to χfollows the extent of branching of the carbon-atom skeleton. We now study the ordering of the constitutional isomers of alkanes with 6 through 10 carbon atoms with respect to C(λ) for various values of the parameter λ. This ordering significantly depends on λ. The difference between the orderings with respect to χand with respect to C(λ) is measured by a function Δand the λ-dependence of Δwas established.